From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0E4DC77B62 for ; Tue, 4 Apr 2023 19:31:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235910AbjDDTbf (ORCPT ); Tue, 4 Apr 2023 15:31:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235844AbjDDTbe (ORCPT ); Tue, 4 Apr 2023 15:31:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3933A2111; Tue, 4 Apr 2023 12:31:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C6820630C3; Tue, 4 Apr 2023 19:31:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0787C433EF; Tue, 4 Apr 2023 19:31:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1680636692; bh=iZeD7ZRu9tfSGLuTP62t6auaUEfXlLmcKZ7Z2/qHEMQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NKpoyy+Yq6eqQbNYmjxqL2awnOyyHtD9l6JPyLyvHjgVoziqxs+++3YxXj1ILg3s7 fThj6+7nxfFmT1cgl4T8Z52FbVv3E1+An1mGocVyxA8KAphD8aJqEfobzBt3Jhc7l5 zcR20po358bnNrXE8ln3SnUEFC/KX/yu2Asz1XdU= Date: Tue, 4 Apr 2023 12:31:31 -0700 From: Andrew Morton To: Christoph Hellwig Cc: Pankaj Raghav , axboe@kernel.dk, minchan@kernel.org, martin@omnibond.com, hubcap@omnibond.com, brauner@kernel.org, viro@zeniv.linux.org.uk, senozhatsky@chromium.org, willy@infradead.org, hch@lst.de, devel@lists.orangefs.org, mcgrof@kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, gost.dev@samsung.com, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 1/5] zram: always chain bio to the parent in read_from_bdev_async Message-Id: <20230404123131.6e8fca22b0a484c8c152492a@linux-foundation.org> In-Reply-To: References: <20230403132221.94921-1-p.raghav@samsung.com> <20230403132221.94921-2-p.raghav@samsung.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, 4 Apr 2023 08:06:55 -0700 Christoph Hellwig wrote: > On Mon, Apr 03, 2023 at 03:22:17PM +0200, Pankaj Raghav wrote: > > zram_bvec_read() is called with the bio set to NULL only in > > writeback_store() function. When a writeback is triggered, > > zram_bvec_read() is called only if ZRAM_WB flag is not set. That will > > result only calling zram_read_from_zspool() in __zram_bvec_read(). > > > > rw_page callback used to call read_from_bdev_async with a NULL parent > > bio but that has been removed since commit 3222d8c2a7f8 > > ("block: remove ->rw_page"). > > > > We can now safely always call bio_chain() as read_from_bdev_async() will > > be called with a parent bio set. A WARN_ON_ONCE is added if this function > > is called with parent set to NULL. > > I'm pretty sure this is wrong. Thanks, I'll drop this v2 series. > I've now sent a series to untangle > and fix up the zram I/O path, which should address the underlying > issue here. I can't find that series. > It will obviously conflict with this patch, so maybe the best thing is > to get the other page_endio removals into their respective maintainer > trees, and then just do the final removal of the unused function after > -rc1.